Statue Without Limitations

When Charles-Olivier Roy, principal of Artisans du Passage, took on the job of reproducing an historic bronze statue, he faced two huge challenges: re-creating a work of art nearly eight feet tall and paying proper homage to one of Canada’s finest sculptors, Louis-Philippe Hébert.

Creating a likeness was not good enough for Roy; he had to produce an exact replica that reflected the full glory of the original piece. Roy met the challenges by turning physical reality into 3D digital reality, which then gave him endless options in the real world.

Scanning of the 7-foot-9-inch statue was done outside the Parliament Building in Quebec City using a Creaform Handyscan 3D scanner.

“I wanted future generations to know how we made it, using 2012 technology to do the work and showing that with the best tools, everything is possible,” says Roy.

At the center of the creative process was Geomagic Studio 3D digital-reality software, which served as the bridge between front-end 3D scanning from hometown company Creaform and 3D printing from 3D Systems.

Scanning in a Day

Roy’s specialty is preserving the past in unique ways. His latest project was undertaken to commemorate the 150-year anniversary of Lévis, a city of 140,000 residents in the eastern part of Quebec, Canada. Roy received funding and technological support to reproduce Louis-Philippe Hébert’s statue of Francis de Gaston, Chevalier (Knight) of Lévis and a national hero. The original statue, created in 1894, resides on a ledge high along the front wall of the Parliament Building in Quebec City.

Geomagic Studio provided the tools to fill hundreds of holes in hidden areas that couldn’t be captured during the scan process.

Roy’s team had one day to bring down the statue from its perch, scan it and return it to its resting place. The Creaform Handyscan 3D scanner was selected not just for its local ties, but because it is portable enough to capture hard-to-reach areas inaccessible to tripod-based scanners.

It took two technicians eight hours to scan the statue at .5mm resolution, which Roy says might be overkill, but will give him very accurate data for any future projects.

Although Geomagic Studio could process the 24-million polygon model all at once, the software was used to break the model into sections to accommodate the 3D printing and ceramic molding processes.

Processing 24-million Polygons

Geomagic Studio software was recommended to Roy by Creaform for processing the massive 3D scan data, which comprise 24-million polygons.

After 3D printing, 110 pieces were assembled, glued and primed to form nine pieces that would fit into the ceramic slurry cylinder to produce molds.

“Geomagic has the power to handle very large scans and provide the detail that we needed to re-create a masterpiece,” says Roy. The software also offers “great tools to edit, fill holes of hidden areas that cannot be digitized, and manage surfacing of the model,” according to Creaform’s Jérôme Baillargeon, who handled the post-processing of the 3D scans.

It took about 16 hours to process the scans into a watertight model using Geomagic Studio, but it would have taken much longer with other software, according to Baillargeon.

“The time-savings come from the fact that Geomagic Studio can handle very heavy files. It was possible to work on the full model instead of having to work on separate sections. All the operations within Geomagic are very fluid.”

Breaking It into Pieces

Although Geomagic enabled the digital model to be processed all at once, Roy faced production limitations in both the 3D printing and the ceramic molding steps: For 3D printing, he had to divide the model into 110 pieces to fit into the production area of the 3D Systems’ ZPrinter. For ceramic molding, the slurry cylinder was limited in size to 24 inches in diameter and 30 inches deep, so Roy needed to assemble the 3D printed parts into nine pieces.

Four layers of primer coating were applied to ensure a smooth finish before pieces were cast in ceramic.

“Geomagic Studio enabled me to divide the pieces exactly where I wanted the seams to be and build the inner surface as well as the skin of the parts,” says Roy. “The trim feature was especially useful for hiding parts needed for assembly in recessed regions, and the shelling feature helped me produce just the right thickness for 3D printing.

“The time I spent in Geomagic Studio saved me a lot of work in fitting the pieces together after 3D printing. The precision of the software gave me confidence that the pieces would be accurate when they were put together for bronze casting.”

From Digital to Physical

Once the statue was divided into pieces, Roy used Geomagic Studio to nest as many pieces as possible into the ZPrinter 310. Printing took about two months, with two setups a day, five or six days a week.

Ceramic shell casting that will be used to cast the piece in bronze.

As the parts came out of the ZPrinter, epoxy was applied, and they were assembled into the nine pieces that would fit into the ceramic slurry cylinder. The parts were covered with four layers of primer coating to remove roughness and provide a smooth finish.

“Bronze casting is very precise,” says Roy. “If you had a fingerprint on the mold, you’d see that print on the final piece.”

After priming, the pieces were covered in silicon to create forms into which wax could be poured to produce molds. Ceramic was then poured inside and outside of the wax molds to create shells. The wax was then removed by a high-pressure steam system called an autoclave. The wax from the shells was recycled.

In the final steps, ceramic shells were fired at high temperatures to harden them and melt remaining wax. The hollow shells were filled with molten bronze. Remaining ceramic was then cracked away from the bronze and the pieces welded together. The statue was finished by sanding, polishing and applying a patina.

Charles-Olivier Roy with the finished bronze statue of Francis de Gaston, Chevalier of Lévis.

The completed statue now awaits a site to be prepared that will accentuate its role as an historical attraction for the city of Lévis.

A Universe of Options

Meanwhile, Roy is producing scale models in bronze and pewter that are expected to go on sale later this year. The one-third scale model was 3D printed from materials donated by EnvisionTEC and output on that company’s Ultra system.

The Lévis project has also spawned a new business model in Roy’s fertile brain: Using 3D scans to create Web-based environments where people can virtually experience heritage sites from the convenience of their homes and purchase replicas of artifacts.

For Charles-Olivier Roy, the universe of options that can be explored by transforming the physical world into 3D digital reality is, well, virtually unlimited.

Bob Cramblitt is a freelancer who writes about 3D digital technologies that transform the seemingly impossible or highly improbable into reality. He can be reached at info@cramco.com.